Histology and histopathology involve the study of cells and tissues under a microscope to diagnose and monitor diseases, such as cancer. Many of the fundamental techniques involved in histological analysis are a century or more old and histological analysis is primarily performed by trained medical professionals.
For standard histological methods, such as creating a digital histological image, current steps include placing a tissue sample inside a plastic cassette with perforated walls that allow fluid access and exposing the cassette to a fluid environment that changes composition over time to provide chemical fixation of the tissue. The tissue is eventually dehydrated and permeated with wax before removing the wax-embedded specimen from the cassette by melting the wax. For each of the processing steps, the tissue sample is generally resting on the floor and/or wall of a plastic cassette providing poor fluid access to those portions of the sample without agitation.
After the wax permeation and removal, the specimen is re-positioned in molten wax and allowed to cool again to fix the specimen in an orientation that permits sectioning slices of the specimen in a plane of choice, optimized for clinical interpretation. The slices are then placed on a slide, stained, and then either viewed directly by a pathologist or presented to an imager for digitization.
The above approach requires manipulation of tissue during processing, incurring labor costs and significant processing time. Furthermore, small specimens including small skin biopsies and biopsies from the gastrointestinal tract where orientation is critically relevant may rotate and bend freely while the cassette is submerged in fluid and exposed to agitation or flow. Those specimens can therefore require significant manipulation and processing time for histological analysis.
Additionally, the full suite of processing steps described above must be completed before a pathologist can begin substantive analysis of the specimen thereby incurring labor costs and delaying diagnoses.